====== Osteoporosis circumscripta ======

[[Osteoporosis]] circumscripta is sometimes observed at the [[skull vault]] and corresponds to the initial stage of [[Paget's disease diagnosis]] of the bone. Differentiating osteoporosis circumscripta from other reasons for [[osteolytic]] images of the [[vault]] may be difficult. 

Bou Antoun et al., report a case of osteoporosis circumscripta of the [[frontal bone]]. A lucent rim seen on CT scan, which was enhanced on gadolinium-enhanced MRI, delineated the abnormal bone. The patient was a 50-year-old woman who had CT scans of the skull for chronic [[sinusitis]]. Pathology examination showed typical bone changes of Paget's disease. The lucent and enhancing rim sign may help in differentiating Paget's disease from other conditions
((Bou Antoun M, Kemel S, Polivka M, Bresson D, Laredo JD. The lucent (CT) and
enhancing (MR) rim, a sign of Paget's disease of the skull: case report. Skeletal
Radiol. 2018 Nov;47(11):1567-1570. doi: 10.1007/s00256-018-2957-x. Epub 2018 May 
5. PubMed PMID: 29730701.
)).